According to an intervention treatment, which is one of treatment methods for an aneurysm, a doctor carries out insertion of a catheter or a guide wire while watching an X-ray fluoroscopic image displayed on a monitor. However, it is difficult to confirm visually a blood vessel on an X-ray fluoroscopic image unless injecting contrast media. On the other hand, if continuously injecting contrast media, a burden onto a patient becomes high. For this reason, conventionally, a roadmap function of displaying a composite image of a past image taken by injecting contrast media and an X-ray fluoroscopic image in real time onto a monitor has been used.
However, such roadmap function cannot cope with a displacement arising along with a state change in the X-ray imaging apparatus (for example, a movement of a bed, or a rotation of an arm), consequently, an image taken by injecting contrast media needs to be re-created each time. Re-creation leads to an increase in the quantity of contrast media to be used, and results in a burden onto the patient. Therefore, recently, a three-dimensional (3D) roadmap function has come into use, which includes preliminarily collecting a three-dimensional blood vessel image on which a blood vessel image is enhanced, and during a treatment, creating a three-dimensional projection image (hereinafter, “volume rendering image”) from the three-dimensional blood vessel image so as to reflect a state change in the X-ray imaging apparatus, and displaying a composite image of the created volume rendering image and an X-ray fluoroscopic image onto a monitor (for example, JP-A 2007-229473 (KOKAI)).
However, even if using the above 3D roadmap function, there is a problem that a displacement of an aneurysm arising along with insertion of a catheter or another tool cannot be coped with.
In other words, according to the 3D roadmap function, a volume rendering image is to be created from a preliminarily collected three-dimensional blood vessel image; however, the three-dimensional blood vessel image is collected in a state where catheter or other tool is not inserted (or is at a starting part of the blood vessel). On the other hand, for example, if a catheter is inserted up to the vicinity of an aneurysm, a bending force of the catheter along a blood vessel and a resilient force are generated, and the blood vessel deforms so as to reduce a bend of the blood vessel. Consequently, not only the position of the blood vessel, but also the position of the aneurysm is displaced from the position at the moment of collecting the three-dimensional blood-vessel image, resulting in that the position of the aneurysm is displayed on a monitor in a displaced state.